2019-12-09 06:20:25

by Christophe Leroy

[permalink] [raw]
Subject: [PATCH] powerpc/irq: fix stack overflow verification

Before commit 0366a1c70b89 ("powerpc/irq: Run softirqs off the top of
the irq stack"), check_stack_overflow() was called by do_IRQ(), before
switching to the irq stack.
In that commit, do_IRQ() was renamed __do_irq(), and is now executing
on the irq stack, so check_stack_overflow() has just become almost
useless.

Move check_stack_overflow() call in do_IRQ() to do the check while
still on the current stack.

Fixes: 0366a1c70b89 ("powerpc/irq: Run softirqs off the top of the irq stack")
Cc: [email protected]
Signed-off-by: Christophe Leroy <[email protected]>
---
arch/powerpc/kernel/irq.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c
index 0aebd7843c73..e2bce937d51f 100644
--- a/arch/powerpc/kernel/irq.c
+++ b/arch/powerpc/kernel/irq.c
@@ -667,8 +667,6 @@ void __do_irq(struct pt_regs *regs)

trace_irq_entry(regs);

- check_stack_overflow();
-
/*
* Query the platform PIC for the interrupt & ack it.
*
@@ -701,6 +699,8 @@ void do_IRQ(struct pt_regs *regs)
irqsp = hardirq_ctx[raw_smp_processor_id()];
sirqsp = softirq_ctx[raw_smp_processor_id()];

+ check_stack_overflow();
+
/* Already there ? */
if (unlikely(cursp == irqsp || cursp == sirqsp)) {
__do_irq(regs);
--
2.13.3